1. Field of the Invention
The present invention relates to a display apparatus, a rotating position detector thereof and a portable computer system having the same, and more particularly, to a display apparatus, a rotating position detector thereof and a portable computer system having the same, which can vary a display mode of a picture according to rotation of a display part.
2. Description of the Related Art
Generally, a display apparatus displays a picture on a display part thereof in either a horizontal or a vertical direction. As shown in FIGS. 1 and 3, a conventional display apparatus 101 is provided with a convertible switch 130 provided in the display part 120 so as to convert a display direction of a picture according to a rotated position of the display part 120.
If a user would like to rotate the display part 120, the display direction of the picture can be changed by manipulating the convertible switch 130 after rotating and disposing the display part 120, thereby varying the display direction of the picture. For example, it may be desirable to display Microsoft Excel files and the like in a horizontal direction as shown in FIG. 2A, and it may be desirable to display general text files in a vertical direction after rotating the display part 120 to 90 degrees (90°) as shown in FIG. 2B.
However, to operate the convertible switch 130 provided in the conventional portable computer, the display part 120 has to be first rotated. Further, even if the convertible switch 130 is erroneously operated under the condition that the display part 120 is not rotated, a picture is output to the display part 120 in an incorrect display direction.
In addition, the convertible switch 130 for converting a display direction of pictures from the conventional portable computer is limited in either a horizontal or a vertical direction. The technology disclosed in Japanese Patent First Publication No. 1996-129557 allows one of four directions to be selected, however, it requires four switches corresponding to four directions.
Further, in the Japanese Patent First Publication No. 1996-129557, there was proposed a direction sensor using mercury. However, the mercury causes environmental problems.
Furthermore, in the Japanese Patent First Publication No. 1999-196397, there was proposed a direction sensor employing a metal ball and a plurality of piezoelectric sensors arranged at regular intervals along the inner circumference of a spherical casing, which can sense the rotated position by pressure-contact of the metal ball and the piezoelectric sensor due to the weight of the metal ball. However, the spherical casing cannot allow the metal ball to keep stable contact with the piezoelectric sensor, so that it is difficult to sense the rotated position correctly.